What’s Growing On Your Bread?

To focus the students’ attention, hold up a piece of bread. Ask students if they know who might use it for food. Prompt them to consider all possibilities (for example, humans, animals, mold, fungus).

Follow up by asking if students have ever seen a rotten apple, moldy slice of bread, etc. Ask, Have you ever wondered what is growing on that old piece of bread?

Point out that when something is rotting, other living things are using it for food. Ask, How do you think these living things travel from place to place? Remind students of the particles they observed in activity, "Dust Catchers." Mention that some of the smallest particles in dust are produced by organisms specifically to be carried to other places. Tell the students they will be observing some living things that spread in this way.

References:

Moreno N., B. Tharp, and J. Dresden. (2011). The Science of Air Teacher’s Guide. Third edition. Baylor College of Medicine.